# terraform [](https://circleci.com/gh/poteto/terraform/tree/master)
Terraform is an Elixir library designed to work with Phoenix. Terraform allows you to incrementally transform an older API into one powered by Phoenix - one endpoint at a time.
View the [demo Phoenix app](https://github.com/poteto/reverse_proxy).
## Installation
1. Add `terraform` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[{:terraform, "~> 0.1.0"}]
end
```
2. Ensure `terraform` is started before your application:
```elixir
def application do
[applications: [:terraform]]
end
```
## Usage
First, add it to `web/router.ex`:
```elixir
defmodule MyApp.Router do
use Terraform, terraformer: MyApp.Terraformers.Foo
# ...
end
```
Then, define a new `Terraformer`, which is also a `Plug`. Any request that goes to a route that isn't defined on your Phoenix app will hit this plug, and you can then handle it:
```elixir
defmodule MyApp.Terraformers.Foo do
alias MyApp.Clients.Foo # example client made with HTTPoison
import Plug.Conn
def init(opts), do: opts
# match specific path
def call(%{method: "GET", request_path: "/v1/hello-world"} = conn, _) do
send_resp(conn, 200, "Hello world")
end
# match all `get`s
def call(%{method: "GET", request_path: request_path, params: params, req_headers: req_headers} = conn, _) do
res = Foo.get!(request_path, req_headers, [params: Map.to_list(params)])
send_response({:ok, conn, res})
end
def send_response({:ok, conn, %{headers: headers, status_code: status_code, body: body}}) do
conn = %{conn | resp_headers: headers}
send_resp(conn, status_code, body)
end
end
```
